Schedule 4 1:45 PM - 3:45 PM [Th-P-15] Evaluation of suppressing forward voltage degradation by using a low BPD density substrate or an epitaxial wafer with an HNDE *Yoshitaka Nishihara1, Koji Kamei1, Kenji Momose1, Hiroshi Osawa1 (1. SHOWA DENKO K.K.(Japan))